We evaluated the morphology of three operatively closed labyrinthine fistulae which were due to acquired middle ear cholesteatoma in three patients. In all three cases the fistula location was in the horizontal semicircular canal. The fistulae were closed by a mixture of bone powder and Tissucol. The layer closing the fistula was in all cases indistinguishable from the bony otic capsule on the postoperative CT.